The interconnection of printed circuit boards to other circuit boards, cables, or other electronic devices is well known in the art. Such interconnections typically have not been difficult to form, especially when the circuit switching speeds (also referred to as signal transition times) have been slow when compared to the length of time required for a signal to propagate through a conductor in the interconnect or on the printed circuit board. However, as circuit switching speeds continue to increase with modern integrated circuits and related computer technology, the design and fabrication of satisfactory interconnects has grown more difficult.
Specifically, there is a continued and growing need to design and fabricate printed circuit boards and their accompanying interconnects with closely controlled electrical characteristics to achieve satisfactory control over the integrity of the signal as it travels through the interconnect to and from the printed circuit board. The extent to which electrical characteristics (such as impedance) of the interconnect must be controlled depends heavily upon the switching speed of the circuit. That is, the faster the circuit switching speed, the greater the importance of providing an accurately controlled impedance within the interconnect.
Connector systems developed for high-speed board-to-board and board-to-cable interconnect applications are replete in the art. In general, an optimum printed circuit board interconnect design minimizes the length of marginally controlled signal line characteristic impedance by minimizing the physical spacing between the printed circuit board and the connector. Also, connector designs which involve relatively large pin and socket connectors with multiple pins devoted to power and ground contacts provide only marginally acceptable performance for high speed printed circuit boards.
Unfortunately, currently available high speed interconnect solutions for board-to-cable applications are typically complex, requiring extremely accurate component designs which are very sensitive to even small manufacturing variations and which, as a result, are expensive and difficult to manufacture. Even then, the performance of the available board-to-cable interconnect systems is becoming only marginally acceptable as switching speeds continue to increase. What is needed is a printed circuit board-to-cable interconnect system that provides the necessary impedance control for high speed integrated circuits while still being inexpensive and easy to manufacture.